Portable optical coherence tomography (OCT) devices and related systems

ABSTRACT

Portable optical coherence tomography (OCT) devices including at least one mirror configured to scan at least two directions are provided. The portable OCT devices are configured to provide a portable interface to a sample that can be aligned to the sample without repositioning the sample. Related systems are also provided.

CLAIM OF PRIORITY

The present application is a continuation of U.S. patent applicationSer. No. 11/535,663, filed Sep. 27, 2006 now U.S. Pat. No. 8,064,989,which claims priority from U.S. Provisional Application No. 60/721,657,filed Sep. 29, 2005, the disclosures of which are hereby incorporatedherein by reference as if set forth in their entirety.

FIELD OF THE INVENTION

The present invention relates to imaging and, more particularly, tooptical coherence imaging devices and systems.

BACKGROUND OF THE INVENTION

Optical Coherence Tomography (OCT) has been around since the early1990's and provides a technique for imaging into samples, such as smallanimals, eyes, tissue, glass and the like. Recent advances haveincreased the imaging speed, which may allow relatively large image sets(such as 3-D volumes) to be quickly generated. Since OCT is high-speed,generally non-contact and non-destructive, it is well suited for imagingdynamics over short time scales, for example, well below 1 second (thebeating of a heart tube in a fruit fly) all the way up to changes over along time scales, for example, days or even longer (tissue growing).

OCT imaging systems are typically divided into several subsystemsincluding an optical engine, a processing unit and a scanning system.The scanning system may provide the interface to the sample that isbeing imaged. Interfaces to date include attachments to stereo zoommicroscopes and table mounted systems for retinal imaging. One retinalimaging interface, for example, Carl Zeiss Meditec's StratusOCT™, looksmuch like a fundus camera. This interface has a chin rest for thepatient and a mechanism for aligning the patient with the OCT imagingsystem. This system typically requires a mobile, upright, andcooperative patient in order to obtain usable OCT images.

SUMMARY OF THE INVENTION

Some embodiments of the present invention provide portable opticalcoherence tomography (OCT) devices including at least one mirrorconfigured to scan at least two directions. The portable OCT devices areconfigured to provide a portable interface to a sample that can bealigned to the sample without repositioning the sample.

In further embodiments of the present invention, the portable OCT devicemay be an OCT probe. The OCT probe may include a relay lens set coupledto the at least one mirror configured to scan at least two directions.

In still further embodiments of the present invention, the OCT probe maybe a non-contact probe that does not make physical contact with thesample. The non-contact probe may further include a first relay lens setconfigured for the non-contact probe. The non-contact probe may beconfigured to make physical contact with a spacer and the spacer may beconfigured to make physical contact with the sample.

In some embodiments of the present invention, the OCT probe may be acontact probe configured to make physical contact with the sample. Thecontact probe may further include a second relay lens set configured forthe contact probe. The contact probe may be configured to receive aprotective cover on the second relay lens set and the protective covermay be configured to make physical contact with the sample.

In further embodiments of the present invention, the OCT probe may beconfigured to receive two or more relay lens sets. In certainembodiments, a first of the two or more relay lens sets may beconfigured for a non-contact probe that does not make physical contactwith the sample. A second of the two or more relay lens sets may beconfigured for a contact probe that makes physical contact with thesample. In further embodiments, a first of the at least two relay lenssets may be configured for imaging through a final optical lensingsystem external to the probe. A second of the at least two relay lenssets may be configured for imaging without the assist of an opticallensing system external to the probe.

In still further embodiments of the present invention, the OCT probe mayfurther include an integrated reference arm. The OCT probe including theintegrated reference arm may further include a beamsplitter. Thebeamsplitter may be configured to receive light and provide a portion ofthe light to an optical path of the reference arm and a remainingportion of the light to the at least one mirror configured to scan atleast two directions of an optical path of the sample.

In some embodiments of the present invention, the OCT probe includes apath length adjustment mechanism configured to provide at least twodifferent optical path lengths through the OCT probe. The path lengthadjustment mechanism may include, for example, a manual adjustmentmechanism or a motor driven adjustment mechanism. The motor drivenadjustment mechanism may include, for example, a mechanical screw,mechanical sliders and/or a motor driven screw.

In further embodiments of the present invention, the OCT probe may be aportable probe, a probe configured to be mounted on a mechanical boom ora probe configured to be mounted to a head of a user.

In still further embodiments of the present invention, a display may beintegrated with the OCT probe. The OCT probe may further include a userinterface configured to operate the display and control operation of anOCT engine in communication with the OCT probe.

In some embodiments of the present invention, the OCT probe furtherincludes a partially reflecting element configured to be mounted on atip of the OCT probe. The partially reflecting element may be configuredto serve as a reflection for a common mode-interferometer.

In further embodiments of the present invention, the OCT probe may beconfigured to generate a reference reflection for a common-modeinterferometer based on reflection internal to the sample.

In still further embodiments of the present invention, the OCT probe mayfurther include multi-path delay lines configured to allow extended scandepth multiplexing.

Some embodiments of the present invention provide optical coherencetomography (OCT) systems including an OCT engine and a portable OCTdevice. The OCT engine includes optics, electronics and/or softwareconfigured to acquire data used to generate OCT images of a sample. Theportable OCT device is in communication with the OCT engine and includesat least one mirror configured to scan at least two directions. Theportable OCT device is configured to provide a portable interface to thesample that can be aligned to the sample without repositioning thesample.

Further embodiments of the present invention provide portable OCTdevices comprising an integrated display.

In still further embodiments of the present invention, the portable OCTdevice may further include a user interface configured to operate thedisplay and control operation of an OCT engine in communication with theportable OCT device. The user interface may include an image acquisitiontrigger configured to acquire images of the sample and/or controlsconfigured to adjust a scan pattern, a scan range, a scan rate and/orimage processing options. The display may be configured to illustratereal time and/or saved images of the sample, system options, systemmodes and/or system error messages.

In some embodiments of the present invention, the display may beconfigured to be mounted substantially perpendicular to the side of theportable OCT device, fold out from the side of the portable OCT deviceor be mounted to the back of the portable OCT device.

Further embodiments of the present invention provide portable OCTdevices including an integrated reference arm.

In still further embodiments of the present invention, the OCT probe mayinclude a beamsplitter configured to receive light and provide a portionof the light to an optical path of the reference arm of the portable OCTdevice and provide a remaining portion of the light to an optical pathof the sample. The beamsplitter may be further configured to receivelight from the optical path of the reference arm and the optical path ofthe sample, recombine the light from the optical path of the referencearm and the optical path of the sample and provide the recombined lightto an OCT engine in communication with the portable OCT device forprocessing.

In some embodiments of the present invention, the reference arm mayinclude zero or one or more turning mirrors, one or more focusing lens,zero or one or more dispersion compensation element, zero or one or moreattenuation elements and a reflecting mirror.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic block diagram illustrating an Optical CoherenceTomography (OCT) system including a portable probe according to someembodiments of the present invention.

FIG. 2 is a schematic block diagram illustrating a contact portableprobe according to some embodiments of the present invention.

FIGS. 3A and 3B are schematic block diagrams illustrating optical lensset configuration of the portable probe of FIG. 1 according to someembodiments of the present invention.

FIG. 4 is a schematic block diagram illustrating a non-contact portableprobe for use in OCT systems according to some embodiments of thepresent invention.

FIG. 5 is a schematic block diagram illustrating a non-contact portableprobe used in conjunction with a spacer according to some embodiments ofthe present invention.

FIGS. 6A and 6B are schematic block diagrams illustrating optical lenssets for use in the non-contact portable probe in FIGS. 4 and 5according to some embodiments of the present invention.

FIG. 7 is a schematic block diagram illustrating a portable probe usedin conjunction with a flexible relay according to some embodiments ofthe present invention.

FIG. 8 is a schematic block diagram illustrating a portable probeincluding interchangeable lens sets according to some embodiments of thepresent invention.

FIG. 9 is a schematic block diagram of illustrating a portable probeintegrated with a reference arm according to some embodiments of thepresent invention.

FIG. 10 is a schematic block diagram illustrating a portable probehaving an adjustable optical path length according to some embodimentsof the present invention.

FIG. 11 is a schematic block diagram illustrating a portable probe foruse in OCT systems according to some embodiments of the presentinvention.

FIG. 12 is a schematic block diagram illustrating a head mounted probefor use in OCT systems according to some embodiments of the presentinvention.

FIG. 13 is a schematic block diagram illustrating portable probes usedin conjunction with controls and/or a display according to someembodiments of the present invention.

FIG. 14 is a schematic block diagram illustrating a portable probe witha common mode path design where the reflection occurs in the probeaccording to some embodiments of the present invention.

FIG. 15 is a schematic block diagram illustrating a portable probe witha common mode path design where the reflection occurs in the sampleaccording to some embodiments of the present invention.

FIG. 16 is a schematic block diagram illustrating a portable probeincluding multi-path delay lines for extended scan depth multiplexingaccording to some embodiments of the present invention.

DETAILED DESCRIPTION OF EMBODIMENTS OF THE INVENTION

The invention now will be described more fully hereinafter withreference to the accompanying drawings, in which illustrativeembodiments of the invention are shown. This invention may, however, beembodied in many different forms and should not be construed as limitedto the embodiments set forth herein; rather, these embodiments areprovided so that this disclosure will be thorough and complete, and willfully convey the scope of the invention to those skilled in the art.Like numbers refer to like elements throughout. As used herein, the term“and/or” includes any and all combinations of one or more of theassociated listed items.

As used herein, the singular forms “a”, “an” and “the” are intended toinclude the plural forms as well, unless expressly stated otherwise. Itwill be further understood that the terms “includes,” “comprises,”“including” and/or “comprising,” when used in this specification,specify the presence of stated features, integers, steps, operations,elements, and/or components, but do not preclude the presence oraddition of one or more other features, integers, steps, operations,elements, components, and/or groups thereof. It will be understood thatwhen an element is referred to as being “connected” or “coupled” toanother element, it can be directly connected or coupled to the otherelement or intervening elements may be present. Furthermore, “connected”or “coupled” as used herein may include wirelessly connected or coupled.As used herein, the term “and/or” includes any and all combinations ofone or more of the associated listed items.

It will be understood that although the terms first and second are usedherein to describe various elements, these elements should not belimited by these terms. These terms are only used to distinguish oneelement from another element. Thus, an element discussed below could betermed a second element, and similarly, a second element may be termed afirst element without departing from the teachings of the presentinvention.

Unless otherwise defined, all terms (including technical and scientificterms) used herein have the same meaning as commonly understood by oneof ordinary skill in the art to which this invention belongs. It will befurther understood that terms, such as those defined in commonly useddictionaries, should be interpreted as having a meaning that isconsistent with their meaning in the context of the relevant art andwill not be interpreted in an idealized or overly formal sense unlessexpressly so defined herein.

Some embodiments of the present invention will now be discussed withrespect to FIGS. 1 through 16. As illustrated therein, some embodimentsof the present invention consist of novel scanning interfaces forOptical Coherence Tomography (OCT) imaging systems. Scanning interfacesaccording to some embodiments of the present invention are portable andmay be portable, thus, the scanner may be aligned with respect to thesubject instead of having to align the subject with respect to thescanner. Interfaces according to some embodiments of the presentinvention may be provided in various configurations, which may include,but are not limited to, a contact probe, a non-contact probe, anon-contact probe with a physical spacer, and the like, the details ofwhich will be discussed further herein.

Conventional implementations of OCT imaging systems typically have afixed sample interface, where the sample is aligned with the location ofthe light coming from the OCT system in order to obtain an OCT image.For example, Carl Zeiss Meditec has the StratusOCT™ where the sampleinterface looks much like a traditional fundus camera with a head andchin rest for the patient. In order to take an image, the patient's headis set in the rest and minor alignment is done to achieve an adequateOCT image. By way of further example, an OCT imaging system may beintegrated with a microscope so that the system provides both OCT imagesof a sample and magnified visual images. The microscope can typically bemoved up and down in the Z direction, but the sample is moved in the Xand Y directions in order to align it with the OCT system.

For many samples, this configuration of the OCT imaging system works,but there is a whole class of samples where it may be very difficult, oreven impossible, to align the sample with respect to the OCT imagingsystems. Thus, according to some embodiments of the present invention,the portable probe designs may allow the sample interface portion of theOCT imaging system to be moved around to align it with the sampleinstead of aligning the sample to the system.

Portable probes, such as handheld probes, according to some embodimentsof the present invention may be useful, for example, in retinal andcorneal imaging in human patients that are not cooperative or arebedridden; retinal and corneal imaging in infants or children; retinaland corneal imaging in animals including mice, rats, pigs, and monkeys;imaging in confined areas, such as the mouth, ear, and rectum; imagingof samples that do not fit in the microscope; and the like. It will beunderstood that the uses described herein are provided for exemplarypurposes only and, therefore, embodiments of the present invention arenot limited to these examples.

Portable probes according to some embodiments of the present inventionmay be lightweight so that it is can be held, moved and controlled bythe user. The OCT system may be relatively compact and, therefore, canbe moved from location to location. Current OCT systems are typicallyfixed in a particular location and the samples or patients must bebrought to that location. A portable OCT system according to someembodiments of the present invention can be taken to the samples orpatients. This may be particularly useful for, for example, bedriddenpatients and for animal applications where moving the animals may bedifficult on the animals or may increase the chance of infection orcontamination. Portable probe OCT imaging systems according to someembodiments of the present invention may be relatively simple and robustwith few moving parts and may need little routine alignment ormaintenance.

Portable probes according to some embodiments of the present inventioncan be, for example, contact probes or non-contact probes. A contactprobe makes physical contact between the probe and the sample. Accordingto these embodiments of the present invention, alignment may berelatively simple since the tip of the probe can be visually placed onthe sample in the desired location for imaging. In some embodiments ofthe present invention, a protective cover may be provided on the probe,for example, over the end of the probe, in order to reduce thelikelihood of contamination of the probe and transfer of material fromone sample to another sample. The protective cover may include, forexample, glass, plastic or other suitable material, and could beflexible or rigid in design. In some embodiments of the presentinvention, the protective cover may be disposable or single use, i.e.,discarded after one use. However, the protective cover may be reusablewithout departing from the scope of the present invention. Theprotective cover may be sterile or capable of being sterilized accordingto some embodiments of the present invention.

A non-contact probe according to some embodiments of the present doesnot contact the sample. These embodiments of the present invention maybe useful for applications where the patient may not want the probe tophysically touch their eye, such as corneal or retinal imaging ofconscious humans. Furthermore, non-contact probes may not pose the samecontamination issues as the contact probe and the possibility oftransfer of material from one sample to another may be reduced. Havingsome space between the probe tip and the sample may also allow the probeto focus the OCT light to a spot which is advantageous for applications,such as corneal imaging or imaging on or near the surface of a sample.

A contact or a non-contact probe according to some embodiments of thepresent invention may be configured to image without the assist of anoptical lensing system external to the probe. For example, a probeaccording to some embodiments of the present invention may provide atelecentric scanning system for imaging cornea or other tissue nominallyon the exterior surface of a sample.

A contact or a non-contact probe according to further embodiments may beconfigured to image with the assist of an optical lensing systemexternal to the probe. For example, according to some embodiments of thepresent invention, a probe may be configured to a non-telecentricscanning system for imaging the retina. In these embodiments, the probeoptics may be designed to provide correct imaging of the retina onlywhen proper consideration is taken of the subject cornea and/or lens ofthe subject eye.

Some embodiments of the present invention provide a spacer inconjunction with a non-contact probe, which may provide a means ofcontrolling the distance between the probe and the sample. For example,the spacer could be attached to the portable probe and could makephysical contact with the sample. The spacer may be configured tocontact the sample remote from the location where the OCT light shineson the sample. For corneal imaging, the spacer could be circular indesign so that it fits around the eye of the patient. This may allow theuser to align the probe with the patient, without having anything touchthe patient's eye, which may be desirable. According to some embodimentsof the present invention, the spacer could have slots or openings orcould be optically clear so that the user can look through the spacer tosee where the probe is aligned. Embodiments of the present inventionincluding a spacer could also be useful for imaging systems where theOCT light is focused as it leaves the probe. It is important to controlthe distance between the probe and the sample since there is a fairlynarrow depth over which OCT imaging occurs and that location in depthneeds to be aligned with the surface or just below the surface of thesample. The spacer may be disposable or reusable without departing fromthe scope of the present invention.

Typical OCT imaging systems generally use light that is infrared or nearinfrared and, therefore, may be difficult or impossible for a user tosee. Adding some visible light in the OCT engine that co-propagates withthe OCT light may allow the user to see where the OCT image is beingacquired on the sample. This visible light may be referred to as anaiming beam and may be generated, for example, by a laser or any otherlight source in the visible wavelength range. This aiming beam may beused in conjunction with any of the embodiments of the present inventiondiscussed herein without departing from the scope of the presentinvention. For example, the aiming beam may be useful in conjunctionwith non-contact embodiments of the present invention discussed herein,where the user may not know exactly where on the sample the OCT image isbeing acquired.

Various embodiments of the present invention will now be discussed withrespect to FIGS. 1 through 16. Referring first to FIGS. 1 through 3,contact probes according to some embodiments of the present inventionwill be discussed. As illustrated in FIG. 1, systems may include an OCTengine 100 connected to a portable probe 101. The OCT engine 100 mayinclude the optics, electronics and/or software used to acquire the dataused to generate OCT images. The portable probe 101 provides aninterface to the sample.

FIG. 2 illustrates various components of portable probes 101′ accordingto some embodiments of the present invention. Light enters along anoptical fiber 110 from the OCT engine (not shown, 100 of FIG. 1). Lightexits the fiber and passes through a collimating assembly 111 at thebase of the handle 115. Once collimated, the light is redirected by oneor more scanning mirrors 112 and continues through a relay lens set 113to the sample 114. Light is scattered from the sample 114 and passesback through the portable probe 101′ to the optical fiber 110 and on tothe OCT engine (not shown).

As illustrated in FIG. 2, there is physical contact between the end ofthe portable probe 101′ and the sample 114. As discussed above, in someembodiments of the present invention, an optional protective cover 116may be provided over the probe 101′. The protective cover 116 may bedisposable or reusable without departing from the scope of the presentinvention. The protective cover 116 may be sterilized or sterilizable.

Referring now to FIGS. 3A and 3B, optical paths through the portableprobe 101′ and potential configurations for different probes that aresuitable for different applications will be discussed. There may beseveral lenses in the optical system, for example, the collimating lens600, two scan lens 601 and 602, the focusing lens 603 and the contactlens 604. It will be understood that the portable probe 101′ of FIGS. 3Aand 3B is provided for exemplary purposes only and that embodiments ofthe present invention are not limited to this configuration. Forexample, other optical lens train designs may be used having fewer ormore than five lenses without departing from the scope of the presentinvention. It will be understood that the focal lengths of the variouslenses may vary based on the type of sample. For example, the focallengths given in FIGS. 3A and 3B are for a human eye sample and a rateye sample, respectively.

Referring now to FIG. 4, portable non-contact probes 101″ according tosome embodiments of the present invention will be discussed. Asillustrated in FIG. 4, the non-contact probe 101″ is similar to thecontact probe 101′ illustrated in FIG. 2, however, the non-contact probe101″ does not actually touch the sample 114. Accordingly, in theseembodiments of the present invention the relay lens set 120′ may bedifferent than the relay lens set 120 for the contact probe 101′.

As discussed above, the light enters the non-contact probe 101″ from anoptical fiber 110 and passes through a collimating assembly 111 at thebase of the handle 115. From there the light is steered by the scanningmirrors 112, passes through the relay lens set 120′, and is incident onthe sample 114. Light is scattered back by the sample 114 and retracesits path through the non-contact probe 101″ before returning to theoptical fiber 110

As discussed above, the non-contact probe 101″ may have a differentrelay lens set than the contact probe 101. For example, the optical lensset of the non-contact probe may be configured as shown in FIGS. 6A and6B. As illustrated therein, the optical lens train system may include acollimating lens 650 and multiple scan lenses 651 and 652. Depending onthe sample, additional lenses may be used. As shown in FIG. 6A for acorneal application 660, a focusing lens 653 is used to focus the lightonto the sample. As shown in FIG. 6B, in retinal scanning applicationsthe light is collimated when it hits the sample 114 and is focused bythe lens in the eye of the sample 114.

Referring now to FIG. 5, non-contact probes according to furtherembodiments of the present invention will be discussed. As illustratedin FIG. 5, the non-contact probe 101″ is used in conjunction with aspacer 130 at the end of the portable probe 101″. The spacer 130contacts the sample 114 remote from the location where the light passesfrom the probe 101″ to the sample 114. The spacer 130 may allow the userto align the portable probe 101″ with the sample 114 and hold the probe101″ steady relative to the sample 114 while not actually touching thesample where the OCT image is being taken as that location may beparticularly sensitive, for example, when the sample 114 is an eye. Thenon-contact probe 101″ of FIG. 5 used in conjunction with the spacer 130may use the same relay lens set 120′ as the non-contact probe 101″ ofFIG. 4, for example, the relay lens set 120′ of FIGS. 6A and 6B. Asdiscussed above, in some embodiments of the present invention, thespacer 130 may have holes or slots or be transparent or partiallytransparent in nature so that the user can see through the spacer tofacilitate alignment of the OCT light with the desired location on thesample 114.

Referring now to FIG. 7, a non-contact probe 101″ used in conjunctionwith a flexible relay system 140 according to some embodiments of thepresent invention will be discussed. The flexible relay system may carryboth the light from the relay lens set 120′ to the sample 114 and thelight coming back from the sample 114. This flexible relay system 140may be implemented using, for example, fiber optics or a multi-lenssystem in a flexible mechanical package. The fiber optic implementationscould be one or more single mode fibers, one or more multimode fibersand/or one or more fibers with multiple cores (single mode or multimode)in each fiber.

Referring now to FIG. 8, portable probes including interchangeable lensrelays according to some embodiments of the present invention will bediscussed. The interchangeable relays may be used in conjunction withcontact 101′ or non-contact 101″ probes (which will be referred tocollectively herein as probe 101) according to some embodiments of thepresent invention. In other words, a single portable probe 101 may beconfigured to switch between contact mode and non-contact mode byreplacing the corresponding relay lens set 151 and 152, respectively. Asillustrated in FIG. 8, one or more relay lens sets 151, 152 can beconnected to the same portable probe 101. A common interface 150 is usedto allow the relay lens sets 151, 152 to connect to the portable probe101. These embodiments of the present invention may allow the user toswitch between types of samples or images by swapping out the relay lensset 151, 152 on the portable probe. In some embodiments of the presentinvention, the system may be configured to recognize a particular relaylens set and set up the rest of the system to accommodate thatparticular relay lens set. This may be done automatically uponconnection of the relay lens set.

Various embodiments of portable probes will now be discussed withrespect to FIGS. 9 through 16. It will be understood that although FIGS.9 through 16 illustrate specific probe embodiments, for example, contactor non-contact probes, embodiments of the present invention are notlimited to this configuration. The features of the embodiments discussedwith respect to FIGS. 9 through 16 may be used in combination with anyembodiment of the portable probe without departing from the scope of thepresent invention.

Referring now to FIG. 9, portable probes having integrated referencearms according to some embodiments of the present invention will bediscussed. As illustrated in FIG. 9, the portable probe includes areference arm, which generally resides in the OCT engine (not shown).The light enters the portable probe 101 through an optical fiber 110,passes through a collimating assembly 111 at the base of the handle 115and is incident on a beamsplitter 200. The beamsplitter 200 sends someof the light to the sample arm optical path 220 and the rest of thelight passes on to the reference arm optical path 221. The ratio of thebeamsplitter can be any realizable value. In some embodiments of thepresent invention, more light will go through the sample arm opticalpath 220 than through the reference arm optical path 221. In the samplearm optical path 220, the light is directed by the scanning mirrors 112,passes through a relay lens set 113, and onto the sample 114. Lightscattered back by the sample 114 follows the sample arm optical path 220in reverse back to the beamsplitter 200.

The rest of the light from the beamsplitter 200 passes to the referencearm optical path 221, which consists of zero, one, or more turningmirrors 201, one or more focusing lenses 202, zero, one, or moredispersion compensation elements 203, zero, one, or more attenuationelements 204, and a reflecting mirror 205. The reflecting mirror 205sends light back down the reference arm optical path 221 to thebeamsplitter 200. The dispersion compensating elements 203 are optionaland may be used in cases where the dispersion in the reference path 221needs to be closely matched to the dispersion in the sample path 220.The attenuation elements 204 are also optional and may reduce the powerlevel returning from the reference arm 221 if there is too much power.The reflecting mirror 205 may or may not be movable to allow adjustmentof the reference arm path length. This adjustment may be done manuallyby the user or automatically by the OCT system without departing fromthe scope of the present invention.

Once the light from the sample and reference arms reach the beamsplitter200 it is recombined and passes through the collimating assembly 111 andback into the optical fiber 110. From this point it returns to the OCTengine (not shown) for acquisition and processing.

Embodiments of the present invention illustrated in FIG. 9 may berelatively insensitive to changes in the optical fiber 110 that connectsthe OCT engine (not shown) to the portable probe 101. Furthermore, theseembodiments may allow the user access to the reference arm and theelements in the reference arm. This may be particularly useful if theelements in the reference arm need to be periodically adjusted ormodified for different samples. The user can easily swap out componentsin the reference arm, such as the dispersion compensation elements 203,or modify an element, for example, change the attenuation introductionby the shutter 204 or the optical path length of the reference bychanging the mirror location 205.

Referring now to FIG. 10, probes with adjustable optical path lengthsaccording to some embodiments of the present invention will bediscussed. As illustrated in FIG. 10, the portable probe 101 has a pathlength adjustment mechanism 210 for the collimating assembly 111. Thispath length adjustment mechanism 210 may allow the user to change theoptical path length through the portable probe 101 to compensate forother variations in path length either in the OCT engine 100 (FIG. 1) orin the sample 114. In embodiments of the present invention illustratedin FIG. 10, the path length adjustment mechanism 210 may be a motordriven adjustment mechanism, such as a mechanical screw that is drivenby a knob at the base of the handle 115 illustrated in FIG. 10, however,embodiments of the present invention are not limited to thisconfiguration. For example, mechanical sliders and motor driven screwsmay be used in place of the mechanical screw. It will be understood thatthe optical path length may be adjusted at other locations in the probeor by other mechanisms, such as electro-optic devices whose index ofrefraction may be altered by applying an electric field across theoptical material and, therefore, path length adjustment mechanisms arenot limited by the examples discussed herein.

Referring now to FIG. 11, a portable probe including a mechanicalfixation according to some embodiments of the present invention will bediscussed. As illustrated in FIG. 11, the portable probe 101 is mountedon a mechanical boom arm 300 that is fixed to a base or console 301. Themechanical boom arm 300 provides a way to align the portable probe 101with the sample 114 without the user having to hold the probe. Alightweight, easy to move probe is used to simplify moving and fixingthe probe relative to the sample. In embodiments of the presentinvention illustrated in FIG. 11, the mechanical boom arm 300 is mountedto a console 301 that contains the OCT engine 100 and a display computer302. Some embodiments of the present invention may include anindependent cart for the mechanical boom arm or a console that only hasthe OCT engine 100 and not the display computer 302. The mechanical boomarm 300 may be counterbalanced so that it is easy to move and easy tofix in a given position. In some embodiments of the present invention,the mechanical fixation could be used in conjunction with holders orfixation mechanisms for the sample. For example, a chin rest could bemounted to the console 301 and the patient's head could be placed on thechin rest and the portable probe moved to align with the patient's eye.The probe could also be rotated to a vertical configuration and samplescould be placed on the console 301 or on another surface. In someembodiments of the present invention, the console may have wheels tofacilitate moving the OCT system between locations instead of bringingthe samples to the OCT system.

Referring now to FIG. 12, a headmounted probe according to someembodiments of the present invention will be discussed. As illustratedin FIG. 12, the portable probe is reconfigured so that it can beheadmounted 400 by the user 401. The light enters the headmounted probe400 via an optical fiber 110 and passes through a collimating assembly111. From there the light bounces off the scanning mirrors 112 and thenthe partial mirror 403. This mirror 403 can be, for example, partiallysilvered or a dichroic that reflects in the wavelength range of thelight from the OCT engine and transmits in the visible wavelengthregion. The purpose of the partial mirror 403 is to allow the user tolook down the path traveled by the OCT light and, thus, may simplifyalignment with the sample. After the partial mirror 403, the lightpasses through a relay lens set 120 and onto the sample. Light scatteredby the sample returns back along the same path until it is reaches theoptical fiber 110 and goes back to the OCT engine. As an option an imageprojector 402 can be used to display an image for the user 401. Thisimage could be the OCT image from the sample 114 or informationregarding the setup and state of the OCT system. The head mounted probe400 may be lightweight so that it can be easily worn by the user withoutslipping or inducing fatigue.

Referring now to FIG. 13, portable probes with controls and/or displaysaccording to some embodiments of the present invention will bediscussed. As illustrated in FIG. 13, the portable probe 101 has zero,one or more controls 500 and zero, one, or more video displays 501.

The controls 500 may allow the user to control the operation of the OCTengine from the probe. These controls communicate with the OCT enginevia the electronic wires 502. It will be understood that althoughelectronic wires 502 are discussed herein, communication between devicescan be accomplished by any means known to those having skill in the art.For example, the controls may communicate with the OCT engine usingwireless communications, such as BLUETOOTH, WiFi and the like withoutdeparting from the scope of the present invention.

One specific control is an image acquisition trigger 503. This may allowthe user a one button operation to control when the system takes imagesof the sample. Other examples may include controls for scan pattern,scan range, scan rate, image processing options, and the like. The otheraddition is one or more optional video displays 501 that may be part ofthe portable probe. This video display would communicate with the OCTengine via the electronic wires 502. The display may illustrate realtime or saved images from the sample. In addition information about theOCT system such as options, modes, and error messages may be displayed.Physically the video display 501 may, for example, be mountedsubstantially perpendicular to the side of the portable probe, fold outfrom the side of the probe, be mounted to the back of the probe (wherethe controls are shown in FIG. 13) or the like.

Embodiments of the present invention illustrated in FIG. 13, may includeadditional electronics in the portable probe that perform some of theimage processing and control that typically happens in the OCT engine.For example, control of the scanning mirrors and image processing anddisplay to support the video display. The communications with the enginecould be individual analog or digital lines or more sophisticatedcommunications such area RS-232, USB, Firewire, or Ethernet.

Referring now to FIG. 14, portable probes with a common mode path designwhere the reflection occurs in the probe will be discussed. A portableprobe with optical fiber 110, collimating assembly 111, scanning mirrors112, and lens relay optics 113 has already been described herein.Accordingly, the details of these elements will not be discussed furtherherein. As illustrated in FIG. 14, a partially reflecting element 600 isprovided at the probe tip (or otherwise placed close to the sample to beimaged), which serves as a reference reflection for a common-modeinterferometer. In a common-mode interferometer, the sample andreference paths may be shared up to a point very close to the sample, sothat any sources of vibration or other noise may be shared between thearms and, thus, may not affect the interferogram. The reflectance of thepartially reflecting element 600 may be designed to increase thelikelihood of optimal reference power on the detector so that shot-noiselimited detection may be achieved. The depth of imaging beyond thereference reflection may be limited by the spectral resolution of thespectral-domain OCT system used, or by the length scan of the timedomain OCT system used.

Referring now to FIG. 15, a portable probe with a common mode pathdesign according to some embodiments of the present invention will bediscussed. A portable probe 101 illustrated in FIG. 15 depends onreflection internal to the sample 610 itself to generate the referencereflection for common-mode interferometry. In some embodiments of thepresent invention, the reference reflection may be optimally close tothe sample since it is inside the sample. The reflection at the surfaceof the sample may be used for this purpose, for example, the cornealsurface reflection at the surface of the eye. In these embodiments ofthe present invention, the amplitude of the surface reflection may bemodified to increase the likelihood of optimal detection signal to noiseration (SNR) by designing the probe optics to have a particularpolarization state or incidence angle on the sample surface to generatea reflection of the desired reflectivity. The depth of imaging beyondthe reference reflection may be limited by the spectral resolution ofthe spectral-domain OCT system used, or by the length scan of the timedomain OCT system used.

Referring now to FIG. 16, a portable probe including mulit-path delaylines for extended scan depth multiplexing according to some embodimentsof the present invention will be discussed. In particular, FIG. 16illustrates a method to address possible limitations of the depth ofimaging of the portable probes of FIGS. 14 and 15.

By placing a series of multi-path delay elements 620, 621, 622 and 623in a portion of the optical path which is common to the reference andsample arms (or alternatively in the source or detector arms of theinterferometer), reflections from widely varying depths within thesample may be multiplexed into the available depth scan range of the OCTsystem used, TDOCT or SDOCT. An example of such a multi-path delayelement is a Fabry-Perot optical cavity placed in the common-mode path.The Fabry-Perot cavity may be constructed from separate reflectiveelements as illustrated in FIG. 16, or it may be constructed from asingle optical element (e.g., a glass mirror blank) having partiallyreflective coatings on both sides. The length of the optical cavity maybe determined by the depth of expected reflections in the sample. Forexample, if it is desired to perform an A-scan of the eye, in which thecornea-lens and cornea-retina optical distances are measured, twooptical cavities may be used, one having a length equal one-half of thecornea-lens distance plus some offset α/2 ((a+α)/2), and another havinga length equal to one-half of the cornea-retina distance plus someoffset β/2 ((b+β)/2). The portion of the incident light which istransmitted directly through both cavities without reflection willgenerate A-scan reflections from the front of the cornea (located at DC)and the back of the cornea, as usual. That portion of the incident lightwhich takes an extra round trip through the first cavity will acquire anextra group delay equal to (a+α), and after reflecting off of the frontsurface of the cornea may interfere with light reflecting off the frontsurface of the lens at a DC offset value of α. Similarly, that portionof the incident light which takes an extra round trip through the secondcavity may acquire an extra group delay equal to (b+β), and afterreflecting off of the front surface of the cornea may interfere withlight reflecting off of the retina at a DC offset value of β. Byextension of this concept, many independent reflections at arbitrarypath lengths may be multiplexed into the available scan range of the OCTsystem used. It will be understood that additional parasiticcorrelations may also be generated at negative distances, and alsoresulting from the spacing between separate individual Fabry-Perotcavities comprising additional Fabry-Perot cavities themselves, howeverthe correlations resulting from these parasitic cavities may be placedoutside the desired imaging range by appropriate spacing of thecavities. In addition, fixed autocorrelation artifacts may be generatedbetween internal reflections, however these latter may be remedied byassuring that the front corneal reflection dominates all otherreflections by a large factor. If this cannot be achieved using areflection within the sample itself, this same concept for multipledistance multiplexing may also be applied to the portable probeillustrated in FIG. 14 in which the reflective element may be designedspecifically for this purpose.

The foregoing is illustrative of the present invention and is not to beconstrued as limiting thereof. Although a few exemplary embodiments ofthis invention have been described, those skilled in the art willreadily appreciate that many modifications are possible in the exemplaryembodiments without materially departing from the novel teachings andadvantages of this invention. Accordingly, all such modifications areintended to be included within the scope of this invention as defined inthe claims. In the claims, means-plus-function clauses are intended tocover the structures described herein as performing the recited functionand not only structural equivalents but also equivalent structures.Therefore, it is to be understood that the foregoing is illustrative ofthe present invention and is not to be construed as limited to thespecific embodiments disclosed, and that modifications to the disclosedembodiments, as well as other embodiments, are intended to be includedwithin the scope of the appended claims. The invention is defined by thefollowing claims, with equivalents of the claims to be included therein.

1. An ophthalmic optical coherence tomography (OCT) system, the systemcomprising: an OCT engine including optics and electronics configured toacquire data used to generate OCT images of a subject; and a portablehousing including a portable scanning interface device in communicationwith the OCT engine, the portable scanning interface comprising: atleast one mirror configured to scan light in at least two non-co-planardirections; and at least one lens set coupled to the at least one mirrorand configured to receive light from the at least one mirror, to focusthe received light onto a structure of an eye of the subject, and toreceive light that is scattered or reflected from the structure of theeye; an optical fiber connecting the housing including the portablescanning interface device to the OCT engine, the optical fiber beingconfigured to guide light from the OCT engine to the portable scanninginterface device; means for aligning the housing including the portablescanning interface device to the structure of the eye without using achinrest to stabilize the subject; means for controlling spacing betweenthe portable interface device and the structure of the eye without usinga chinrest to stabilize the subject; means for setting acquisitionparameters for imaging the structure of the eye; and means foracquiring, processing and displaying three dimensional OCT image data ofthe structure of the eye in real-time.
 2. The OCT system of claim 1,wherein the portable scanning interface device comprises a non-contactprobe that does not make physical contact with the sample and whereinthe non-contact probe further comprises a first lens set configured forthe non-contact probe.
 3. The OCT system of claim 1, wherein theportable scanning interface device comprises a contact probe configuredto make physical contact with the sample and wherein the contact probefurther comprises a second lens set configured for the contact probe. 4.The OCT system of claim 1, further comprising a display in the portablehousing integrated with the portable scanning interface device such thatthe portable scanning interface device and the integrated display areconfigured to communicate with the OCT engine.
 5. The OCT system ofclaim 1, wherein the portable scanning interface device furthercomprises an integrated user interface in the portable housingconfigured to control an operation of the portable scanning interfacedevice in communication with the OCT engine.
 6. The OCT system of claim5, wherein the operation comprises at least one of triggering an imageacquisition, controlling a scan pattern, controlling a scan rate, andcontrolling an image processing option, the user interface comprising:an image acquisition trigger configured to acquire images of the sample;and at least one control configured to adjust a scan pattern, a scanrange, a scan rate and/or image processing options.
 7. The OCT system ofclaim 5, wherein the display is configured to illustrate at least one ofa real time image of the sample, a saved image of the sample, a systemoption, a system mode, and a system error message.
 8. The OCT system ofclaim 5, wherein the integrated display is configured to be mountedsubstantially perpendicular to the side of the portable scanninginterface device, fold out from the side of the portable scanninginterface device, or be mounted to the back of the portable scanninginterface device.
 9. The OCT system of claim 1: wherein the portablescanning interface device is configured to receive one of the at leasttwo lens sets; wherein at least one of the at least two lens set isconfigured to image a retina; and wherein at least one of the at leasttwo lens set is configured to image a cornea.
 10. The OCT system ofclaim 1: wherein the portable scanning interface device is configured toreceive one of the at least two lens sets; wherein at least one of theat least two lens set is configured to image a sample without makingphysical contact with the sample; and wherein at least one of the atleast two lens set is configured to image a sample with making physicalcontact with the sample.
 11. The OCT system of claim 1: wherein themeans for controlling spacing between the portable interface device andthe structure of the eye without using a chinrest to stabilize thesubject comprises a counterbalanced mechanical boom arm to which theportable interface device is mounted.